As is known, tank melting furnaces are used in factories for the continuous production of glass items.
This type of furnace is constituted substantially by a melting chamber with a tank in which a mixture of components of the glass melts and from which the glass flows out in the liquid state through a neck located on the bottom of the tank in order to reach the processing area, and by a regeneration chamber, in which the exhaust gases that originate from the molten glass tank cool down.
These plants operate according to regenerative thermal cycles, recovering the heat that originates from the melting tank by means of regenerators, constituted by layers of stacked refractory bricks, typically made of magnesite, which are arranged inside the regeneration chamber and are supported by a supporting structure.
It is preferable to use bricks having an octagonal base, arranged in a honeycomb configuration and with staggered layers, so as to define inline vertical paths and articulated paths for the exhaust gases that originate from the tank and which, by cooling, descend toward the lower region of the regeneration chamber by passing through the layers of bricks.
However, bricks of the cross-shaped type or solid bricks are also used and are in any case arranged in staggered side-by-side layers so as to create paths of the described type.
The exhaust gases contain sulfates, which during cooling are deposited on the walls of the bricks.
Over time, due to this deposition, such paths are obviously subject to becoming clogged, forcing to shut down the furnace and therefore to interrupt the production cycle in order to perform cleaning operations.
To avoid the need to resort to furnace shutdown, currently preference is given to a method for cleaning the paths of the regenerator which provides for the ignition of methane gas burners at the base of the regenerators. The increase in temperature inside the regenerators melts the sulfates and accordingly makes them fall onto the bottom of the regeneration chamber, which is cleaned by an operator assigned to maintenance of the plant, working in the lower part of the chamber below the supporting structure for the layers of bricks.
This method is not devoid of drawbacks.
The foremost is the fact that the operator must work inside the regeneration chamber, in the lower part, exposing himself to extremely high temperatures, typically comprised between 450 and 650° C.
Moreover, this method causes wear of the lowest layers of bricks (proximate to which the burners are located), which, brought to operating conditions that are at the limit of their thermal and mechanical strength, are spoiled and crushed until they cause collapses of the stack and failure of the surface on which they rest.
Another drawback is linked to the fact that during this scrubbing process the furnace operates in pressure conditions that are higher than the design operating pressure.
The aim of the present invention is to devise a method for cleaning tank melting furnaces that is capable of solving the observed drawbacks.
Within this aim, an object of the invention is to prevent the operators assigned to maintenance of the plant from being forced to work in high temperature conditions.
Another object of the invention is to devise a cleaning method that is not harmful for the structure of the regeneration chamber.
A further object of the invention is to clean the regenerator without having to modify for this purpose the operating conditions of the furnace.